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<h1 class="title">client.conf(5)</h1>
<h2 class="title"><a name="NAME">Name</a></h2>
client.conf - client configuration file for cups (deprecated on macos)
<h2 class="title"><a name="DESCRIPTION">Description</a></h2>
The <b>client.conf</b> file configures the CUPS client and is normally located in the <i>/etc/cups</i> and/or <i>~/.cups</i> directories.
Each line in the file can be a configuration directive, a blank line, or a comment. Comment lines start with the # character.
<p><b>Note:</b> Starting with macOS 10.7, this file is only used by command-line and X11 applications plus the IPP backend.
The <b>ServerName</b> directive is not supported on macOS at all.
Starting with macOS 10.12, all applications can access these settings in the <i>/Library/Preferences/org.cups.PrintingPrefs.plist</i> file instead.
See the NOTES section below for more information.
<h3><a name="DIRECTIVES">Directives</a></h3>
The following directives are understood by the client. Consult the online help for detailed descriptions:
<dl class="man">
<dt><a name="AllowAnyRoot"></a><b>AllowAnyRoot Yes</b>
<dd style="margin-left: 5.0em"><dt><b>AllowAnyRoot No</b>
<dd style="margin-left: 5.0em">Specifies whether to allow TLS with certificates that have not been signed by a trusted Certificate Authority.
The default is "Yes".
<dt><a name="AllowExpiredCerts"></a><b>AllowExpiredCerts Yes</b>
<dd style="margin-left: 5.0em"><dt><b>AllowExpiredCerts No</b>
<dd style="margin-left: 5.0em">Specifies whether to allow TLS with expired certificates.
The default is "No".
<dt><a name="DigestOptions"></a><b>DigestOptions DenyMD5</b>
<dd style="margin-left: 5.0em"><dt><b>DigestOptions None</b>
<dd style="margin-left: 5.0em">Specifies HTTP Digest authentication options.
<b>DenyMD5</b> disables support for the original MD5 hash algorithm.
<dt><a name="Encryption"></a><b>Encryption IfRequested</b>
<dd style="margin-left: 5.0em"><dt><b>Encryption Never</b>
<dd style="margin-left: 5.0em"><dt><b>Encryption Required</b>
<dd style="margin-left: 5.0em">Specifies the level of encryption that should be used.
<dt><a name="GSSServiceName"></a><b>GSSServiceName </b><i>name</i>
<dd style="margin-left: 5.0em">Specifies the Kerberos service name that is used for authentication, typically "host", "http", or "ipp".
CUPS adds the remote hostname ("name@server.example.com") for you. The default name is "http".
<dt><a name="ServerName"></a><b>ServerName </b><i>hostname-or-ip-address</i>[<i>:port</i>]
<dd style="margin-left: 5.0em"><dt><b>ServerName </b><i>/domain/socket</i>
<dd style="margin-left: 5.0em">Specifies the address and optionally the port to use when connecting to the server.
<b>Note: This directive is not supported on macOS 10.7 or later.</b>
<dt><b>ServerName </b><i>hostname-or-ip-address</i>[<i>:port</i>]<b>/version=1.1</b>
<dd style="margin-left: 5.0em">Specifies the address and optionally the port to use when connecting to a server running CUPS 1.3.12 and earlier.
<dt><a name="SSLOptions"></a><b>SSLOptions </b>[<i>AllowDH</i>] [<i>AllowRC4</i>] [<i>AllowSSL3</i>] [<i>DenyCBC</i>] [<i>DenyTLS1.0</i>] [<i>MaxTLS1.0</i>] [<i>MaxTLS1.1</i>] [<i>MaxTLS1.2</i>] [<i>MaxTLS1.3</i>] [<i>MinTLS1.0</i>] [<i>MinTLS1.1</i>] [<i>MinTLS1.2</i>] [<i>MinTLS1.3</i>]
<dd style="margin-left: 5.0em"><dt><b>SSLOptions None</b>
<dd style="margin-left: 5.0em">Sets encryption options (only in /etc/cups/client.conf).
By default, CUPS only supports encryption using TLS v1.0 or higher using known secure cipher suites.
Security is reduced when <i>Allow</i> options are used.
Security is enhanced when <i>Deny</i> options are used.
The <i>AllowDH</i> option enables cipher suites using plain Diffie-Hellman key negotiation (not supported on systems using GNU TLS).
The <i>AllowRC4</i> option enables the 128-bit RC4 cipher suites, which are required for some older clients.
The <i>AllowSSL3</i> option enables SSL v3.0, which is required for some older clients that do not support TLS v1.0.
The <i>DenyCBC</i> option disables all CBC cipher suites.
The <i>DenyTLS1.0</i> option disables TLS v1.0 support - this sets the minimum protocol version to TLS v1.1.
The <i>MinTLS</i> options set the minimum TLS version to support.
The <i>MaxTLS</i> options set the maximum TLS version to support.
Not all operating systems support TLS 1.3 at this time.
<dt><a name="TrustOnFirstUse"></a><b>TrustOnFirstUse Yes</b>
<dd style="margin-left: 5.0em"><dt><b>TrustOnFirstUse No</b>
<dd style="margin-left: 5.0em">Specifies whether to trust new TLS certificates by default.
The default is "Yes".
<dt><a name="User"></a><b>User </b><i>name</i>
<dd style="margin-left: 5.0em">Specifies the default user name to use for requests.
<dt><a name="UserAgentTokens"></a><b>UserAgentTokens None</b>
<dd style="margin-left: 5.0em"><dt><b>UserAgentTokens ProductOnly</b>
<dd style="margin-left: 5.0em"><dt><b>UserAgentTokens Major</b>
<dd style="margin-left: 5.0em"><dt><b>UserAgentTokens Minor</b>
<dd style="margin-left: 5.0em"><dt><b>UserAgentTokens Minimal</b>
<dd style="margin-left: 5.0em"><dt><b>UserAgentTokens OS</b>
<dd style="margin-left: 5.0em"><dt><b>UserAgentTokens Full</b>
<dd style="margin-left: 5.0em">Specifies what information is included in the User-Agent header of HTTP requests.
"None" disables the User-Agent header.
"ProductOnly" reports "CUPS".
"Major" reports "CUPS/major IPP/2".
"Minor" reports "CUPS/major.minor IPP/2.1".
"Minimal" reports "CUPS/major.minor.patch IPP/2.1".
"OS" reports "CUPS/major.minor.path (osname osversion) IPP/2.1".
"Full" reports "CUPS/major.minor.path (osname osversion; architecture) IPP/2.1".
The default is "Minimal".
<dt><a name="ValidateCerts"></a><b>ValidateCerts Yes</b>
<dd style="margin-left: 5.0em"><dt><b>ValidateCerts No</b>
<dd style="margin-left: 5.0em">Specifies whether to only allow TLS with certificates whose common name matches the hostname.
The default is "No".
</dl>
<h2 class="title"><a name="NOTES">Notes</a></h2>
The <b>client.conf</b> file is deprecated on macOS and will no longer be supported in a future version of CUPS.
Configuration settings can instead be viewed or changed using the
<b>defaults</b>(1)
command:
<pre class="man">
defaults write /Library/Preferences/org.cups.PrintingPrefs.plist Encryption Required
defaults write /Library/Preferences/org.cups.PrintingPrefs.plist TrustOnFirstUse -bool NO

defaults read /Library/Preferences/org.cups.PrintingPrefs.plist Encryption
</pre>
On Linux and other systems using GNU TLS, the <i>/etc/cups/ssl/site.crl</i> file, if present, provides a list of revoked X.509 certificates and is used when validating certificates.
<h2 class="title"><a name="SEE_ALSO">See Also</a></h2>
<a href="man-cups.html?TOPIC=Man+Pages"><b>cups</b>(1),</a>
<b>default</b>(1),
CUPS Online Help (<a href="http://localhost:631/help">http://localhost:631/help</a>)
<h2 class="title"><a name="COPYRIGHT">Copyright</a></h2>
Copyright &copy; 2021-2022 by OpenPrinting.

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